1. Field of the Invention
This invention relates to an apparatus for connecting an image recording device such as a printer or an electronic copying machine to sheet processors. More particularly, the invention is directed to a device capable of connecting an otherwise incompatible sheet handling type processor with an image recording apparatus through an intermediate transfer unit.
2. Discussion of the Related Art
Sheets recorded by an image recording apparatus such as a printer or an electronic copying machine are generally transferred to a processor, such as a sorter. A binder or other type of finishes, may also be connected to the image recording apparatus. For example, in Japanese Patent Unexamined Publication No. 173695/1988, a binder is directly connected to an electronic copying machine and the recorded sheets produced by the electronic copying machine are bound into books and discharged to a discharge tray.
In the related art, when a sorter, a binder, or other finisher is incompatible with the image recording apparatus in terms of sheet transfer direction, such incompatibility may be eliminated by interposing a sheet transfer direction changing mechanism between the two incompatible components. This allows the outgoing recorded sheet from the image recording apparatus to be received by the downstream processor, e.g., 90.degree. rotated.
In the example disclosed in Japanese Utility Model Unexamined Publication No. 29344/1989, the sheet transfer direction changing unit is disposed between the electronic copying machine and a paper folding unit so that large size sheets can be oriented to be received properly by the sheet folding unit.
The sheet transfer direction changing unit may also be disposed between an electronic copying machine and a sorter. In order to change the sheet travel direction by 90.degree., a rotary disk-like member may be used, as disclosed in Japanese Patent Unexamined Publication No. 176752/1989, or two rollers may be provided, each being driven at different speeds, as disclosed in Japanese Patent Unexamined Publication No. 43042/1989.
Thus, in a processing system with an incompatible processor and image recording apparatus, a solution to the incompatibility is to provide means for changing the sheet transfer direction to facilitate the operation at the incompatible processor.
In the related art image recording apparatus, a processor to be connected to a device such as an online finisher is, in most cases, of the same origin as that of the image recording apparatus or of the same or compatible design both mechanically and electronically, and their controllers are also designed so that they can be used in combination.
It may be occasionally required that a sophisticated processor such as a saddle stitcher, a stapler, or a binder be connected to a system consisting of the image processing apparatus and the related art binder or sorter. This further complicates system connection and control.
In such a case, the processors to be connected downstream to the image recording apparatus may be incompatible with each other because they are made by different manufacturers. Nevertheless, it is required that such optional processor be able to properly process the recorded sheets while connected to a main system with which it is basically incompatible.
However, when an incompatible processor is connected downstream of the main system, the controller of the image recording apparatus may not be able to manage the controllers of its processors because their controlling procedures may, in many cases, be different from one another.
For example, if a jam occurs in the image recording apparatus or the online finisher, and the jam is eliminated but has produced some defective pages, the final processor may bind the defective recorded sheets containing into books. With the connection of the final processor to the main system in an existing manner, the production of defective books cannot be eliminated or prevented.
If a purge tray is provided to divert defective recorded sheets from the final processor, the above problem may be overcome. However, the provision of a purge tray may require extensive modification and investment.
Therefore, in the event of such a failure in the main system, the defective recorded sheets received by the final processor must be destroyed and the same sheets must be produced again. This results in a waste of sheets.
In addition to functional incompatibility among controllers, incompatibility in mechanical design, i.e., height, must also be taken into consideration when connecting incompatible components, e.g., the online finisher and the final processor.
When connecting the online finisher to an incompatible processor downstream of the image recording apparatus, it is the final processor that is adjusted to align the height of the three components. However, it is cumbersome to make such an adjustment. Further, the related art online finisher has a sheet transfer path to be connected to the upstream component, but not, to accommodate a downstream processor. Thus, to connect a processor downstream to the related art online finisher, it is required that the online finisher be largely retrofitted, which is expensive.